Liquid phase oxidation of ethylbenzene on pure and metal doped HS-AlF3

Pure and doped high surface aluminium fluorides (HS-AlF3) with different active metal species (Fe, Mn, V, and Nb) were prepared by a sol–gel fluorination technique. The resulting solids were characterised by MAS NMR, pyridine photoacoustic spectroscopy, NH3 TPD and O2 chemisorption. As probe reaction for the catalytic behaviour of the samples the selective liquid phase oxidation of ethylbenzene (EB) to acetophenone (AP) was used. The catalytic behaviour strongly depends on the type and strength of the surface acid sites formed and on the oxidation capacities of the active metal sites. The best results were obtained (high EB conversion and selectivity towards AP) with the vanadium and iron doped aluminium fluoride, whereas the vanadium containing sample tends to leach under the reaction conditions.